U.S. Pat. No. 4,128,750 to Castonguay et al. discloses a circuit breaker operating mechanism having powerful mechanism springs to assist in closing the breaker contacts and for rapdily opening the contacts under a stored spring force upon the occurrence of a fault condition. When circuit breakers are employed in a stand-by condition, the breaker is charged by either a manual handle or motor driven mechanism to provide a spring force in excess of 100 pounds for closing the breaker contacts while retaining sufficient force to trip the breaker. When the charged stand-by condition is reached, a command signal can then be applied to the breaker operating mechanism instructing the breaker contacts to close. If the breaker is equipped with the undervoltage release accessory apparatus described in U.S. Pat. No. 4,097,831 to Jencks et al., an undervoltage condition, such as could appear with temporary power outages, will cause the undervoltage release tripping mechanism to trip the breaker not only from a closed position, but also from a charged stand-by condition while the contacts are already open. Since some of the stored spring force is depleted when closing the breaker contacts, the breakers are designed to withstand a force somewhat less than the fully charged spring force. The condition of tripping a breaker from an open contact position through a fully charged mechanism spring is termed "crashing" the breaker mechanism. Repeated "crashing" operations will result in reduced mechanism life.
The purpose of this invention is to provide an adapter assembly for use with charged-type circuit breakers which employ an undervoltage release accessory for preventing undervoltage tripping when the circuit breaker is in an open contact "charged" position.